1. Field of the Invention
Embodiments relate generally to III-V based gated semiconductor structures and gated semiconductor devices. More particularly, embodiments relate to enhanced performance within III-V based gated semiconductor structures and gated semiconductor devices.
2. Description of the Related Art
III-V based semiconductor structures and semiconductor devices often provide superior performance in certain applications in comparison with silicon based semiconductor structures and semiconductor devices. For example, gallium arsenide III-V based semiconductor structures and semiconductor devices are particularly common within microwave applications.
In addition, group III nitride based semiconductor structures and semiconductor devices, and in particular group III nitride transistors, are desirable for high power electrical circuit applications since group III nitride transistors are capable of carrying large currents (i.e., greater than about 1.5 amps/mm normalized to gate periphery) at high operating electric field strengths (i.e., greater than several megavolts/cm).
Group III nitride transistors comprise as an active semiconductor material at least one group III elemental nitride. Since the common group III elemental nitrides include aluminum, indium and gallium nitrides, several binary, ternary and quaternary compositions exist for group III nitride transistors.
Commonly, a group III nitride transistor comprises a substrate over which is successively layered at least two group III nitride material layers having different bandgap characteristics. A buffer layer is located closer to the substrate and a barrier layer is located upon the buffer layer and generally has a wider bandgap. Due to the difference in bandgaps a 2 dimensional electron gas (2DEG) is induced at the interface of the buffer layer and the barrier layer. The two dimensional electron gas (2DEG) typically is highly localized near the heterojunction interface, but largely within the buffer layer that has a narrower bandgap.
While III-V semiconductor structures, including group III nitride transistors, provide many performance advantages, III-V semiconductor structures are nonetheless not entirely without problems. In that regard, III-V semiconductor structures, like many other semiconductor structures and related semiconductor devices, are subject to improvement in operating capabilities and performance.
Since III-V semiconductor structures are likely to remain popular within several applications where the enhanced operating characteristics of III-V semiconductor devices that derive from operation of the III-V semiconductor structures are primary considerations, desirable are additional III-V semiconductor structures and methods for fabricating the additional III-V semiconductor structures, with enhanced operating capabilities and performance.